Power, Connection, and Cable Specifications

To supply power to the router, connect power cables to a separate, dedicated power source for each power supply and attach the cables to the terminal studs on the circuit breaker box. Most sites distribute power through a main conduit that leads to frame-mounted power distribution panels, one of which might be located at the top of the rack that houses the router. A pair of cables (one input and one return) connects each set of terminal studs to the power distribution panel.

There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on the circuit breaker box. You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity.

Figure 29 shows a typical source cabling arrangement.

Power plant ground and chassis ground must be connected to the same building ground.

Table 17 summarizes the specifications for the grounding and power cables, which you supply. The accessory box shipped with the router includes the cable lugs that attach to the terminal studs of the circuit breaker box (see Figure 28). (The cable lug shown in Figure 28 is also used for the grounding the chassis.)

Before router installation begins, a licensed electrician must attach a cable lug to the grounding and power cables that you supply. A cable with an incorrectly attached lug can damage the router (for example, by causing a short circuit).

Table 17: DC Power and Grounding Cable Specifications

For field-wiring connections, use copper conductors only. For other electrical safety information, see Electrical Safety Guidelines and Warnings.

Power cords and cables must not block access to router components or drape where people could trip on them.

Figure 30shows how to attach the power cables. The power cables attach to the 1/4–20 UNC terminal studs located on the circuit breaker box— the input set of studs is labeled –48V and the return set is labeled RTN(+). The nuts and locking washers used to secure the power cable lugs on the terminal studs are preinstalled on the studs.

The tool for loosening or tightening the nuts on the terminal studs is a 7/16-in. hexagonal-head external drive socket wrench, or nut driver, with a minimum of 30 lb-in. (3.5 Nm) tightening torque.

Do not substitute a metric nut driver or wrench. A tool that does not fit the nuts exactly can damage them. If a 7/16-in. tool is not available, use pliers or an adjustable wrench.

For information about the DC power supply, including electrical specifications and a description of components, see Power Supply. For instructions on connecting the DC power and grounding cables during initial installation, see Connecting Power to the Router. For instructions on replacing a DC power cable, see Disconnecting and Connecting Power.